SYNTHETIC STUDIES ON NATURAL ISOCOUMARINS AND ISOCARBOSTYRIL DERIVATIVES HAVING AN ALKYL SUBSTITUENT AT THE 3-POSITION: TOTAL SYNTHESIS OF SCOPARINES A AND B, AND RUPRECHSTYRIL

Two isocoumarins, scoparines A and B, having n-propyl group at the 3-position, and a new isocarbostyril, ruprechstyril, bearing n-pentyl substituent at the 3-position were synthesized via Sonogashira coupling of the corresponding aromatic halides and alkynes, followed by regioselective 6-endo-dig cyclization.